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Passive smoking doubles babies’ risk of tooth decay

A study from Kyoto University has found that babies who are exposed to tobacco smoke at the age of four months are twice as likely to suffer from tooth decay before their third birthday than those who are not.

While passive smoking has long been recognised as a risk factor for dental problems in children, the study’s findings aim to help quantify the extent of the phenomenon. A total of 55 per cent of adults smoke in Kyoto, where the study took place.

Interestingly, there was no increased risk for babies who were born to mothers who smoked during their pregnancy, at least in terms of oral health. The research was based on 76,920 Japanese children who were born between 2004 and 2010.

The study’s authors said: “Exposure to second-hand smoke at four months of age, which is experienced by half of all children of that age in Kobe City, Japan, is associated with an increased risk of caries in deciduous teeth.

“Although these findings cannot establish causality, they support extending public health and clinical interventions to reduce second-hand smoke.”

Although the researchers were keen to stress that the study does not prove a causal link between smoke inhalation and tooth decay, children who had been exposed to tobacco smoke had lower levels of sialic acid than children who had not. Sialic acid is important for preventing plaque building up on the teeth, and a lack of it can lead to tooth decay.

Overall, toddlers had a 14 per cent chance of developing tooth decay, which rose to 20 per cent if they lived with a smoker. A total of 27.6 per cent of under-threes directly exposed to tobacco smoke suffered from tooth decay.

The research has been published in the British Medical Journal (BMJ). Previous studies have also linked exposure to tobacco smoke to increased levels of tooth decay.